Question

What is the equation (in slope-intercept form) of the line passing through the points (6, 1) and (0, 4)?

y=-1/2x+2
y=-1/2+ 11/2
y=-2x+4
y=-2x+8

Suppose that the daily cost and revenue functions for the production and sale of x stopwatches are given by C(x) = 6x + 160 and R(x) = 10x where C(x) and R(x) are in dollars.

How many watches would need to be produced and sold each day in order to break even?

10
16
80/3
40

Answer 1

first find the slope ....
in your case that would be (4-1)/(0-6) = 3/-6 = -1/2

so that eliminates the last two choices.

try subbing (6,1) into the other two.
It does not satisfy either one, so there is something wrong with your answers.

should be :
let the equation be y = (-1/2)x + b
sub in (6,1)
1 = (-1/2)(6) + b
b = 4

the equation should be
y = (-1/2)x + 4

(notice the second point satisfies my equation)


for the second question,
set 10x = 6x + 160 and solve for x, real easy !